Cleaning composition



Patented Oct. 16, 1945 CLEANING COMPOSITION George W. Gregg, South Bend,Ind., assignor to Bendix Aviation Corporation, South Bend, Ind., acorporation of Delaware No Drawing. Application June 19, 1940,

Serial No. 341 ,275

Claims. (01.252-12'l) This invention relates to a cleaner and to themethod of mixingand preparing the cleaner. It has for one object toprovide 'a cleaner suitable for cleaning metal parts although its use isnot limited to metal. One important use of the cleaner is to remove oil,grease, carbon, s ms; the stain from ethyl gasoline and contaminationand foreign matter generally from metal and metal parts. Another objectof the invention is to pro- 1 vide a cleaner of the type indicated whichrequires no special equipment and has no injurious efiects on the metalor metal parts themselves. Another object is to provide acleaner for usein cleaning metals which have ,been treated with .dicincmic and anodictreatments and which will not iniure such metals or destroy orcounteract the efiects of such treatments. Metals which are commonlygiven such treatments are'zinc die-casttags and aluminum castings.

is highly stable and non-corrosive and which has a sufdciently highflash point to be safe in use without special precautions or specialapparatus and which can be used cold.

The cleaner of this invention in one arrangement includes generally thefollowing materials or their equivalents in the proportions indicatedalthough some materials may be omitted, others may be substituted andthe proportions may be varied:

v. Blending and thinning agent (sodium '01- ehromate) 2 Water (sumcientto dissolve the soap) 20 The specific materials above given arementioned by way of illustration rather than by way of limitation. Manysubstitutions of equivalent materials are possible and many variationsin the relative proportions of the materials are possible. One specificexample of a substitution is that in the solvent either theethylene-dichloride or the propylene-dichloride may be omitted and theremaining solvents increased proportionally.

While the cleaner has its present most import- V Another-object is .toprovide a cleaner of the type indicated which drocarbons may be used.

ant use in cleaning metal, it may be used for other purposes to cleanother materials, among them china and earthenware, bakelite and plasticgenerally, and many other materials.

It is important that a cleaner of this sort be as free from fire hazardas possible. When'mixed with the materials and in the proportions aboveindicated, the cleaner has a flash point of approximately degrees and afire point of approximately degrees under agitation. When the materialis not agitated, it will stratify; and when so stratifled, it has aflash point of approximately degrees. It has also the property that theleast inflammable materials come to the top and hence reduce the firedanger. Another important purpose, as a result of the stratification, isthat those materials which come to the-top protect the more volatilematerials which tend to lie lower in the mixture and prevent theirevaporation and thus prevent waste. In general. the material which comesto the surface when the material is allowed to stand is a mixture ofwater and soap and sodium bichromate. Other materials may, of course, bemixed with the upper.

stratum but those mentioned make up the upper ody of that stratum.

in general, the material is used without any agitation. Afterpreparation it is put into an open tank of suitable size for the'size'of the parts which are to be cleaned. The Parts are put into it, allowedto soak for a few minutes and then removed. Should agitation be desired.it may be applied and tends to hasten the action as is generally thecase with almost all cleaners.

but agitation is not necessary for commercial use and success.

As above noted the materials and proportions set out in the table aboveare illustrative rather than limiting. The solvent has primarily thefunction of weakening the bond between certain foreign material and themetal to which it has adhered so that the foreign material, includinggreases, gums and the like, is removed from the metal without beingfully dissolved. The purpose of the solvent is, therefore. to dissolvewhatever it is that causes the bond of contamination and the foreignmatter generally to adhere to the metal. While unchlorinatedhydrocarbons mi ht be used, their solvent power and ability are lesChlorinated hydrocarbons have a greater solvent ability and areefi'ective on a larger number f materials. Only two hydrocarbons arespecifically mentioned in the table above. However. any chlorinatedhydrocarbons or any mixture of hy- The soap is used for its detergentaction. It tends to surround the particles of foreign matter. It tendsto break down the surface tension of the foreign matter andcontamination. The solvent present breaks the-bond between the foreignmatter and the metal, and the soap tends to surround the matter afterits bond is broken.

When the foreign matter has thus been broken away from the metal andsurrounded with soap, it sinks or floats, depending upon its weight; andwhen the cleaner is quiet, as when it is out of use, the foreign mattersinks when stratification of the material occurs and settles to thebottom as sludge. It does not go to the top of the material and scum isnot formed. Practically all of the foreign matter settles to the bottomas sludge. While vegetable oil soap has been mentioned and ispreferable, others may be used. One advantage of vegetable soap is thatit dissolves readily in cold water.

The penetrant which is mentioned may be any of the cresols or phenol orcresylic acid or tar acid. Preferably, as above mentioned, a tar acidoil of the low boiling range is used which contains not less than fiftyper cent tar acid. The penetrant, which is the third ingredient in thelist set out above, penetrates the contamination to permit the rapidaction of the solvent and the detergent. The penetrant has to someextent a solvent action itself. The penetrant is properly considered asprimarily a softener.

The coupling agent, which may also be considered a blending agent, ispreferably normal butyl alcohol. In the cleaner of this invention, thebutyl alcohol acts as a coupling agent for the solvent and the detergentand it thins the emulsion; hence, reducing the drag-out." When partswhich have been cleaned are removed from a body of the cleaner, thatportion of the cleaner which sticks to them and is carried out and lostis called the drag-out." It is, of course, an advantage to reduce thisas far as possible and one of the effects of the coupler is to thin thematerial, particularly, the emulsion, and to limit or reduce thedrag-out. The coupler is not merely a thinner, however, but it causes achemical coupling of the molecules of one material with the other. Amere thinner such as waterwould not have the true coupling efiectrequired.

The anti-foaming agent has the effect of further reducing the drag-out.If the material were highly foamy, which would otherwise be the case, alarger quantity of the cleaner would be lost as drag-out when thearticles which have been cleaned are removed through the foam becauseappreciable quantities of foam would adhere to the articles and be lostwith them. Other alcohols might be used, including methyl alcohol, and avariety of denatured alcohols might be used, including the formula Fl3.Experience has shown that although many alcohols may be used, syntheticethyl alcohol is of particular advantage. It is uniform and cheaper thannatural grain alcohol and readily obtainable.

A preservative is used to prevent rancidity. Animal fats and greases arefrequently taken into the cleaner during its use. It is important toprevent rancidity of these products present in the cleaner or in thesludge which settles from it. Since the rosin is present in the cleaner,it acts upon the fats as soon as they are taken up. The fats tend tomove promptly into the sludge and since the sludge may be present forquite a long while rancidity would occur were it not for the presence ofthe preservative. The fats tend might be used but rosin is asatisfactory one and is suillciently cheap for normal commercial use.

The blending and thinning agent, referred to as the seventh ingredientin the above table, ef- I fects a coupling between the solvent and thesoap solution and a blending between the soap solution and the tar acidsand between the double soap solution and the solvent which is partiallycoupled by the butyl alcohol. Sodium bichromate is referred to as asuitable blending and thinning agent. Without the presence of the sodiumbichromate, the soap would have a tendency to separate, particularlyupon stratification of the material when quiet. Also, an unstableemulsion is produced. The advantage of the unstable emulsion is thatwhen the dirt is separated from the metal from which it is beingcleaned, it is not suspended in the cleaner but is permitted to sink.While sodium bichromate is a suitable blending and thinning agent, thereare others, among them potassium bichromate. Before the sodiumbichromate is added, there is a clear soap solution. When the acids areput in they tend to curdle the soap and this curdling is prevented orthe tendency for its occurrence is overcome by the sodium bichromate orother blending and thinning agent.

The eighth ingredient in the list above is water. It acts as a solventfor some of the materials. Other materials might be used instead.Alcohol might be used but it would not be as satisfactory as thedetergent action which soap has with water would be reduced ordestroyed. The presence of water effects a more complete removal of thecontamination by increasing the detergent action of the soap.

In considering the proportions of the ingredients above, it has beensaid that they may be varied. For example, the solvent might be presentfrom ten to thirty per cent of the total and other similar variationsmight be made.

While the material may be mixed in several different ways and while theingredients do not have to be put in a fixed order, experience has shownthat the following is a satisfactory order of mixing:

1. The tar 'acid 'is put into the mixing vat.

2. The solvent. and the soap are mixed separately and the butyl alcoholis added. This mixture of solvent, soap solution and butyl alcohol isthen put into the tar acid.

3. The rosin may be added to the soap or it may be present in thealcohol when the alcohol is added to the solvent and soap solution.

4. The sodium bichromate is then added.

5. During the adding and mixing the material is agitated in whatevervessel it is being mixed in. Mixing takes place at ordinary roomtemperatures and when it is completed the desired quantity of thecleaner may be removed and used.

I claim:

1. In a stratified surface cleaner for cleaning relatively hardmaterials, the combination of the following stratifying materials: asolvent comprising one of the chlorinated hydrocarbons, a detergentcomprising a vegetable oil soap, :1 penetrant comprising a tar acid.oil, a coupling agent comprising normal butyl alcohol, an antifoamingagent comprising ethyl alcohol, a preservative comprising rosin, ablending and thinning agent comprising sodium bichromate, and water.

2. In a surface cleaner for cleaning relatively hard materials, thecombination of the following materials: a solvent comprising one of thechlorinated hydrocarbons, a detergent comprising a vegetable oil soap, apenetrant comprising a 50 per cent tar acid oil, a coupling agentcomprising normal butyl alcohol, an anti-foaming agent comprising ethylalcohol, a preservative comprising rosin, a blending and thinning agentcomprising sodium bichromate, and water.

3. In a surface cleaner for cleaning relatively hard materials, thecombination of the following materials: a solvent comprising one of thechlorinated hydrocarbons, a detergent comprising a vegetable oil soap, apenetrant comprising a tar acid oil, a coupling agent comprising normalbutyl alcohol, an anti-foaming agent comprising denatured ethyl alcohol,a fat preservative comprising rosin, a blending and thinning agentcomprising sodium bichromate, and water.

4. A cleaning bath for metallic articles adapted to be immersed thereinand whose surfaces are contaminated with oils, greases, gums, fats,

' carbons and other contaminating substances,

said bath consisting of a solvent comprising one of the chlorinatedhydrocarbons selected from the group consisting of ethylene-dichlorideand propylene-dichloride, approximately 20 per cent; a detergentcomprising a vegetable oil soap, approximately 10 per cent; a penetrantselected from the group consisting of cresol, phenol, cresylic acid andtar acid oil, approximately 33 per cent; a coupling agent comprisingnormal butyl alcohol, approximately 8 per cent; an anti-foaming agentcomprising ethyl alcohol, approximately 6 per cent; a preservative forpreventing rancidity of the contaminating substances removed from themetal articles by the bath, said preservative comprising rosin,approximately 1 per cent; a blending and thinning agent selected fromthe group consisting of sodium bichromate and potassium bichromate,approximately 2 per cent; and water, approximately 20 per cent.

5. A cleaning bath for metallic articles adapted to be immersed thereinand whose surfaces are contaminated with oils, greases, gums, fats,carbon and other contaminating substances, said bath consisting of asolvent comprising ethyl- GEORGE W. GREGG.

